Extracorporeal biliary lithotripsy. Review of experimental studies and a clinical update.

PURPOSE

To identify the technical and physical principles of extracorporeal biliary lithotripsy that are clinically relevant, and to review the patient series published to date.

DATA IDENTIFICATION

Studies published since 1983 identified through a computerized search of MEDLINE and extensive hand searching of bibliographies in identified articles.

STUDY SELECTION

Twenty-nine studies done in vitro or in animals and 21 studies in humans assessing biliary lithotripsy.

DATA EXTRACTION

Based on an understanding of experimental determinants of fragmentation, we assess and explain the differences in the results from the clinical studies. The conclusions concerning overall clinical efficacy and safety are emphasized.

RESULTS OF DATA ANALYSIS

Extracorporeal shock waves will safely fragment the gallstones of 80% to 100% of selected patients. However, the rate of satisfactory fragmentation (defined as the persistence of fragments only 3 to 5 mm in diameter or less) varies widely among the studies (22% to 78%); this discrepancy depends partly on differing characteristics of stone populations. For patients presenting with solitary stones of 20 mm in diameter or less, 90% will be stone-free within 6 to 9 months after lithotripsy; moreover, the success of lithotripsy determines the rapidity and extent of fragment dissolution. Bile-duct-stone lithotripsy is reserved for patients in whom endoscopic stone extraction and intracorporeal lithotripsy, with or without direct contact dissolution, have failed. Lithotripsy achieves ductal clearance in 55% to 85% of patients.

CONCLUSIONS

Extracorporeal lithotripsy is safe and effective in selected patients, and has a definite role to play in managing patients with biliary stone disease. Its role in the coming years will depend on technical improvements in the generators, a tailored approach to complementary dissolution or extraction, and effective prophylactic therapy for preventing gallstone recurrence.